Effect of TiB ₂ and Boron Additions on the Stability of Wurtzite‐Type Boron Nitride at High Temperatures and Pressures

Shock‐synthesized wurtzite‐type BN(w‐BN) and mixtures of w‐BN–TiB 2 and w‐BN–ß were treated at high temperatures and pressures. The effect of TiB 2 and boron additions on the transformation of w‐BN to zinc blende‐type BN(z‐BN) was studied at 1000° to 2200°C and 55 to 68 kbars. The formation region of z‐BN was shifted toward higher temperatures by TiB 2 additions and toward lower temperatures by boron additions.